Topical steroids

Definition and Clinical Role

Topical steroids, also known as topical corticosteroids, are synthetic derivatives of the naturally occurring hormone cortisol (hydrocortisone). They are designed to be applied directly to the skin or mucous membranes to treat a wide range of inflammatory, allergic, and autoimmune skin conditions.

These drugs exert local anti-inflammatory, antipruritic (anti-itch), vasoconstrictive, and immunosuppressive effects, making them first-line treatments in dermatological practice. They are categorized based on potency, ranging from mild (Class VII) to super potent (Class I).

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Mechanism of Action

Topical corticosteroids exert their effect primarily through glucocorticoid receptors in skin cells:

1. Binding to cytoplasmic glucocorticoid receptors

2. Translocation into the nucleus

3. Modulation of gene transcription

   • ↑ Anti-inflammatory proteins (e.g., lipocortin-1)

   • ↓ Pro-inflammatory cytokines, prostaglandins, and leukotrienes

They inhibit:

• Phospholipase A2 (which decreases arachidonic acid production)

• Cyclooxygenase-2 (COX-2)

• Pro-inflammatory interleukins and TNF-α

The net result is reduced inflammation, erythema, edema, and pruritus.

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Therapeutic Indications

Topical corticosteroids are indicated for the treatment of:

• Atopic dermatitis

• Contact dermatitis (allergic and irritant)

• Psoriasis

• Seborrheic dermatitis

• Lichen planus

• Discoid lupus erythematosus

• Nummular eczema

• Lichen simplex chronicus

• Pruritus ani and vulvae

• Insect bites

• Intertrigo

• Keloids and hypertrophic scars

• Pemphigoid and bullous dermatoses

• Vitiligo (adjunctive use)

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Classification by Potency (UK & US Classification)

Potency	Example Generic Names	Typical Use Sites
Class I – Super Potent	Clobetasol propionate 0.05% Halobetasol propionate Diflorasone diacetate	Thick plaques, palms, soles
Class II – Potent	Betamethasone dipropionate 0.05% Mometasone furoate 0.1% Fluocinonide	Localized lesions, resistant eczema
Class III – Upper-Mid	Betamethasone valerate 0.1% Desoximetasone Fluticasone propionate	Trunk, extremities
Class IV – Mid Strength	Triamcinolone acetonide 0.1% Hydrocortisone butyrate	Moderate lesions
Class V – Lower Mid	Hydrocortisone valerate Desonide cream 0.05%	Children, face, intertriginous areas
Class VI – Mild	Alclometasone dipropionate Desonide 0.05%	Sensitive skin
Class VII – Least Potent	Hydrocortisone acetate 1% (OTC) Hydrocortisone 0.5%	Diaper area, face, infants

Common Generic Topical Corticosteroids

1. Hydrocortisone (0.5%, 1%, 2.5%)

   • Mild; OTC and prescription

   • First-line for children and sensitive skin areas

2. Clobetasol propionate

   • Super potent; not for long-term use

   • Effective in recalcitrant psoriasis, lichen planus

3. Betamethasone (dipropionate, valerate)

   • Widely used moderate-to-potent steroids

   • Suitable for many dermatoses

4. Mometasone furoate

   • Potent but well-tolerated

   • Once-daily use, good safety profile

5. Triamcinolone acetonide

   • Intermediate strength

   • Versatile use on body surfaces

6. Desonide

   • Mild; pediatric and facial use

7. Alclometasone dipropionate

   • Mild to moderate; sensitive skin

8. Fluticasone propionate

   • Potent; safe with limited systemic absorption

9. Fluocinonide

   • Potent; commonly used for psoriasis

10. Halobetasol propionate

    • Super potent; short duration use

11. Desoximetasone

    • Moderate to high potency

12. Diflorasone diacetate

    • Super potent

13. Hydrocortisone butyrate

    • Moderate strength

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Formulations and Routes of Administration

• Creams: Water-based, suitable for moist or weeping lesions

• Ointments: Occlusive, better for dry/scaly lesions

• Lotions: Hairy areas or large surfaces

• Gels: Scalp, mucosal surfaces

• Foams: Convenient, cosmetically elegant

• Sprays and Solutions: Scalp or areas requiring minimal friction

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Dosing and Duration

• Typically applied once or twice daily

• Short-term use (5–14 days for potent agents)

• Long-term use only with low potency agents under supervision

• Application amount: Measured in Fingertip Units (FTUs)

  • 1 FTU ≈ 0.5 g covers ~2 adult palm sizes

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Pharmacokinetics and Systemic Absorption

Factors increasing systemic absorption:

• High-potency formulations

• Large surface area application

• Prolonged duration

• Occlusion (e.g., bandages)

• Thin or damaged skin (e.g., infants, elderly)

• Intertriginous areas, face, genitalia

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Adverse Effects

1. Local Effects:

   • Skin atrophy

   • Telangiectasia

   • Striae

   • Perioral dermatitis

   • Acneiform eruptions

   • Hypopigmentation

   • Tachyphylaxis

   • Contact allergy

2. Systemic Effects (rare unless prolonged/high dose):

   • HPA axis suppression

   • Cushingoid features

   • Hyperglycemia

   • Growth suppression in children

   • Osteoporosis

   • Glaucoma/cataracts (with periorbital use)

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Contraindications

• Untreated bacterial, fungal, or viral skin infections

• Rosacea

• Perioral dermatitis

• Acne vulgaris

• Hypersensitivity to corticosteroids or formulation excipients

• Use in infants under 1 month (unless mild agents under medical supervision)

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Precautions

• Use lowest effective potency for shortest duration

• Avoid high-potency steroids on face, genitals, intertriginous areas

• Use intermittently for chronic conditions (e.g., weekend therapy)

• Monitor for skin thinning and signs of systemic absorption

• Pediatric use should be closely monitored

• Avoid abrupt withdrawal after prolonged use

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Pregnancy and Lactation

• Generally considered safe for limited use

• Prefer low-potency topical corticosteroids

• Avoid long-term or large-area potent steroid use

• Topical use during breastfeeding is acceptable but avoid application to nipples

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Drug Interactions

• Minimal systemic interaction due to topical route

• Caution when used with other immunosuppressants

• Avoid concurrent use with other topical irritants or peeling agents

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Patient Counseling Points

• Apply thin layer to affected skin only

• Do not use as moisturizer

• Avoid application to open wounds unless directed

• Wash hands after application

• Do not cover with occlusive dressings unless advised

• Report persistent irritation, thinning, or discoloration

• Do not abruptly stop high-potency use – taper if needed

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Monitoring Parameters

• Symptom resolution

• Skin integrity (atrophy, telangiectasia)

• Growth in children (with long-term use)

• HPA axis (ACTH stimulation test in chronic high-potency users)

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Notable Combination Products

• Betamethasone + Clotrimazole (Lotrisone®)

• Hydrocortisone + Miconazole (Daktacort®)

• Clobetasol + Salicylic acid (Diprosalic®)

• Triamcinolone + Nystatin (Mycolog®)

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Regulatory and Access Status

• Many low-potency steroids (e.g., 1% hydrocortisone) are OTC

• Potent steroids require prescription (Rx-only)

• Restricted use in pediatrics, sports, cosmetics, and animal care in some regions